What are underlying "system hardware devices" in computer systems?

[askingquestion]

Hi, I am not English native and I need help by understanding the underlined text as:
"In broad terms, an OS kernel performs three primary jobs.

1. It provides the interfaces needed for users and applications to interact with the computer.
2. It launches and manages applications.
3. It manages the underlying system hardware devices.
In more granular terms, accomplishing these three kernel functions involves a range of computer tasks, including the following:
..."
From https://www.techtarget.com/searchdatacenter/definition/kernel
Can somebody please explain it?
Thanks in advance.

 

[berkeman]

Welcome to PF.

It looks like your link has a pretty good discussion of the hardware resources that are being referred to. Certainly the computer memory is one such hardware resource, but it lists several other examples as well...

** loading and managing less-critical OS components, such as device drivers;

** organizing and managing threads and the various processes spawned by running applications;

** scheduling which applications can access and use the kernel, and supervising that use when the scheduled time occurs;

** deciding which nonprotected user memory space each application process uses;

** handling conflicts and errors in memory allocation and management;

** managing and optimizing hardware resources and dependencies, such as central processing unit (CPU) and cache use, file system operation and network transport mechanisms;

** managing and accessing input/output devices such as keyboards, mice, disk drives, USB ports, network adapters and displays; and

** handling device and application system calls using various mechanisms such as hardware interrupts or device drivers.

 

[jedishrfu]

One way to understand how an OS works is to imagine you are in charge of a group of people in an office. People come in to the office with various work requests and you distribute them to your workers to handle. WHen the workers complete a request, they bring it back to you and you send it back to the people who requested it.

In that moment, you are acting like a computer OS. The people bringing in work requests are the users of your "computer". They enter commands into the computer ie "the work requests" and the computer distributes them to other processes to be completed. You keep track of and monitor the processes waiting for them to complete before notifying the user that their work request or task is complete.

Notice that for a human to do this, they may need to write things down to keep track of who is doing what and how long it took them and who you should return the completed work to. The computer OS does this using tables , tables and tables to manage its resources and work being done.

When you get too many requests at the same time then you must prioritize them and decide which of your workers to assign the work request to. This is how computers manage the workload so as not to run out of resources in the middle of a work request and crash the system.

As an example, you would evaluate a work request first:
- decide how important it is
- decide if it can be split up and handled by multiple people
- decide how much time, memory, diskspace will be needed
- launch the processes to do the work
- monitor their progress
- place some work requests in a queue
- manage the flow of work ie the number of jobs running and their memory needs
- release new work requests when computer resources have freed up
- do garbage collection on memory and disk to optimize execution
- run background tasks to scan for viruses and other malware...

 

[askingquestion]

Can you explains to me the meaning of granular in the expression granular terms?
What is the meaning of it?

 

[phinds]

Can you explains to me the meaning of granular in the expression granular terms?
What is the meaning of it?

granular = composed of lots of small parts. Also, in some contexts, "detailed".

 

[askingquestion]

granular = composed of lots of small parts. Also, in some contexts, "detailed".

And what is the meaning of underlying computer hardware?
What is underlying (hardware)?

 

[Arjan82]

The hardware that underlies the software. In other words: the hardware that the software is running on.

 

[phinds]

What is underlying (hardware)?

The hardware that lies under the software

 

[FactChecker]

The germs "granular" and "underlying hardware" are referring to the fact that the kernel contains the lowest level of software that deals directly with every detail (every small "grain") of the hardware requirements. The hardware device drivers are part of the kernel. There is no other level of software in between the kernel and the hardware that makes it easier for the kernel software to deal with the hardware requirements.